| 摘要 |
PURPOSE:To obtain perfectly spherical, fine polyester powder having excellent smoothness, touch, filling properties and toughness, by colliding a heated, molten polyester resin with a high-velocity pressurized gas to flow together, and injecting them from a nozzle to polymerize the resin in a solid state. CONSTITUTION:A polyester resin having an average polymerization degree less than 30 or a reduced viscosity less than 0.25 is heated and molten. The molten polyester resin is collided with a high-velocity pressurized gas at an angle of incidence theta of more than 30 deg. to the direction of the gas flow to flow together, and thereafter the mixture is injected from a nozzle. The thus-obtained perfectly spherical, fine resin powder having a maximum particle diameter of 100mu or less is polymerized in a solid state at a reduced pressure or in a heated, inactive atmosphere. It is preferable that the pressure of a gas at which the gas is blown into a nozzle is 0.5kg/cm<2>G or more. It is preferable to use a polyethylene terephthalate resin or a copolymerized polyester resin containing principally ethylene terephthalate units as a polyester resin. |
